Yes by removing all the rooms that you had.
Just remove your Cache from your computers C: drive, and restart Runescape Client.
no you can not sell your house on runescape.
No, Your RuneScape House is based on your Construction Level.
Clear your cache, or restart the computer then try again it should work.
Camelot
It is not a RuneScape problem, maybe you have a virus or not enough memory.
Go to the place with the house icon in varrock.
in the volcano at michaels house
Yes.
open the door
Yes.
Restart the game client, make sure you log out properly. Also you could try clearing your cache.